How to Remove a Reverse Osmosis Filter

Hi everyone! I saved my least favorite kitchen project of the kitchen renovation for last–removing our reverse osmosis water filter and replacing our kitchen faucet. I’m going to break this project down into two posts. This post will focus on removing the reverse osmosis filter.

old faucet and reverse osmosis filter faucet
Our old boring faucet and the filter faucet.

I know people love their reverse osmosis filters, but we rarely used ours (we used the chilled water in the fridge) and it took up a ton of space under our sink cabinet. And, since storage is at premium in our tiny kitchen, it needed to go.

reverse osmosis storage tank
This is only have of the reverse osmosis filter

I’ve installed bathroom faucets before, and they’re very straight forward. So, I was most worried about the reverse osmosis filter. If you haven’t seen one before, you can see from the pictures below that there are a lot of large pieces and a lot of tubes that go in to water and drainage pipes. I was worried about removing the wrong one or breaking something. So, it took me a month of scouring YouTube videos on how to remove a reverse osmosis filter before I felt comfortable tackling the project.

reverse osmosis filter
And, here’s the second part on the other side of the cabinet.

Not to spoil the ending, but because of the awkward corner cabinet and our giant garbage disposal, I got about 75% of the way through the project and had to call in our fantastic handyman on a Saturday afternoon for his help to finish the project. So, I’m going to talk about how to do both projects, but I’ll let you know when I stopped and our handyman took over.

Removing the Reverse Osmosis Filter

The steps to remove the reverse osmosis filter aren’t that hard–the hardest part is accessing the connections to remove it.

When working with any plumbing, a few words of wisdom: make sure you truly feel comfortable doing what you’re doing. If you have an inkling of doubt, please call a licensed plumber. The last thing you want is a flood in your newly renovated kitchen, or to be without water until a professional can come out and fix the problem. I am a DIYer, so what I am describing is how I completed this project. Please don’t take it as professional advice.

Step 1: Turn Off the Water

water shutoff
The water input valve for my filter

Before you do any plumbing project, make sure you turn off the water. To turn off the water, find the water shut off under your cabinets, and turn the handle until it’s all the way off. To test it, turn your faucet on and run the water until it stops. If your set up is anything like mine, I had three water shut offs under the sink–one for the filter, one for the cold faucet, and one for the hot faucet. I turned them all off before starting.

I’m a nervous nelly, so not only do I turn off the local shut off valves, but a lot of times, I also turn off the whole house water because I’m still new to plumbing projects and like having that as a security blanket to give me a little more confidence for the projects.

Not going to lie, for me this was easier said than done. Because my sink is installed in a corner cabinet, I had to angle myself in the cabinet and around the garbage disposal to even reach the water shut offs or any part of the faucet. This is ultimately why I stopped mid-way and called my handyman. I was too uncomfortable laying in the cabinet, and I couldn’t get the correct angles to use the tools I needed to.

Step 2: Drain the Reverse Osmosis Storage Tank

Before removing anything, make sure you drain the reserve tank. This is super easy–just turn your filter faucet on and drain the water until it stops running. That will drain the water in the tank. Once it stops flowing, you can turn the faucet off again.

reverse osmosis filter faucet
You can see the handle is up, so the filter is open to drain. I let it drip for a few minutes to make sure I got out as much as I could.

This step is important so you’re not trying to drag a tank of water out from under your faucet. It’s super heavy when it’s empty, so it would be ten times worse if you don’t do this first.

Step 3: Disconnect all the Tubing

This can be a little messy (and by messy, I mean wet), so make sure you have some old towels or rags under the cabinet with you to dry things up as the water drips. Because even though you drained your tank, there will be some water left in the tubing that will drain out when you disconnect it.

drainage pipes
See that tubing going in to the central drainage pipe at the top of the screen. That piece had to come out (it’s called a T piece, since it’s shaped like a T). After I did that, I took that 3-way piece and took it to Home Depot and bought a replacement for $2 that was straight and easily replaced it.

To disconnect them, I just had to twist with my hands, but I did have some pliers and a wrench just in case something was stuck.

The pieces I disconnected were:

  • The drainage tubing connected to the T piece
  • The tubing connecting the storage tank and the filter
  • The tubing connecting the filter to the water line
  • The tubing connecting the storage tank and the faucet

I took all that tubing out from under the sink, so I could more easily remove pieces and see what I was working with.

Step 4: Remove the Reverse Osmosis Water Tank

After everything was disconnected, I lifted the water tank out from under the sink. (This was actually as easy it sounds).

reverse osmosis storage tank
Here it is hanging out with Sadie’s toy in our living room.

Step 5: Remove the Reverse Osmosis Water Filter

Lift the water filter out from under the sink and put it aside. (Also, as easy as it sounds).

reverse osmosis filter
Look how gross it was–yuck!

Step 6: Remove the Filter Faucet

under the sink
The hole on the left with the white tubing coming out of it is the filter faucet. I couldn’t reach that, no matter how hard I tried.

This is where I had to call my handyman. No matter how I wedged myself, I couldn’t get a grip on the nut that holds the faucet underneath the sink. My handyman, of course, slid right in there and had it out in less than 5 minutes.

hole in the sink

Step 7: Plug the Hole in your Countertop (or Replace it With a Soap Dispenser)

We wanted to install a soap dispenser in this extra hole, but as is our luck in this house, the hole was too small to hold any current day soap dispensers we can find. So, for now, we installed a brushed nickel cover while we search the internet for a soap dispenser that may fit.

To install the cover, it works best if you have two people. You simply place the little foam piece over the hole.

Then place the cover into the hole, and while one person holds the cover in place, the second person goes underneath the sink and screws a large plastic nut on to the cover until it’s tight. That’s it!

The soap dispensers work the same way, if you want to place one of those instead.


Step 8: Fix any Issues with the Plumbing Before you Turn the Water Back On

If by removing the filter, you had to remove pieces of plumbing (like I had to remove the T piece), or if you now have an open hole draining from your water line, you’ll need to fix these before turning the water back on.

In terms of the water line, I was lucky in that we had a separate water shutoff for the filter. So, I have kept the water shutoff off, and we put a little plug in it that you can buy at Home Depot or any plumbing supply store.

For the drainage pipe that we removed the T pipe from, I went and bought a straight PVC pipe the same width from Home Depot. That way when I loosened all the drainage pipe connections and removed the T piece, I just slid the new piece right in and it worked perfectly with the rest of the existing pipes.

Then tighten all the nuts again, and make sure your drain pipe after the
p-trap (the loop at the bottom that looks like a sideways p), is slowly draining downward.

Now’s the moment of truth–turning your water back on and looking for leaks. My dad taught me to wipe every pipe connection down with a paper towel before turning the water on, so you can easily touch each connection and see if there’s a slow water leak. If there is, turn the water back off, reposition or tighten the nuts again, and repeat the process. Sometimes, you’ll get lucky the first try, and sometimes (like when I replaced the bathroom vanity), it’ll take you 2 hours.

Make sure you run the water on full blast for 5-10 minutes (really, you should run it that long) to make sure there’s no leaking.

Once you feel confident it’s not leaking anywhere, I’d still come back the next few days and check to make sure there wasn’t a super slow leak that you just missed the day before. I normally leave a bowl underneath the connections for the first week, or a towel, just to be safe (thanks, Dad, for that tip!).

Voila! We did it! We removed this massive reverse osmosis filter and have added a whole cabinet full of storage space for us to use–mostly for cleaning supplies and grocery bags.

Not the cleanest yet, but still so great!

Everything we currently have under the sink cabinet where the filter was, used to be in a 12″ lower cabinet in our kitchen. Now that’s completely empty! I’m sure we’ll fill it in two seconds, but it’s so great to be able to gain some of our cabinet space back, especially by removing something we weren’t using.

Let me know if you have any questions! On Friday, I’ll talk about the last medium-sized kitchen project: replacing the faucet! Then we’re basically completely done!


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